Survey of Globular Clusters with the AKARI FIS for the Intracluster Dusts

  • Published : 2010.04.06

Abstract

In search of the intracluster dusts, we have made a survey of globular clusters (GCs) with the Far-Infrared Surveyor (FIS) aboard AKARI, the Japanese infrared space satellite. The GCs are thought to host dust particles that are condensed from the material injected by the cluster asymptotic giant branch (AGB) stars. However, attempts to detect dust emission from GCs had not been successful until a significant amount of far-infrared (FIR) emission was detected close to the NGC 7078 center by the ISO observations (Evans et al. 2003). Recent FIR observations by the AKARI (Matsunaga et al. 2008) and the Spitzer Space Telescope (Boyer et al. 2006; Barmpy et al. 2009) reported a tentative detection of the dusts in NGC 5024 and NGC 6341, and also confirmed the previous ISO dust detection from NGC 7078. We have observed 17 selected GCs in four FIS wavebands at 65, 90, 140, and 160 micrometers. Each observation covers about $10'{\times}10'$ area centered at each GC. The resulting images show extended structures and/or blobs around the GCs. The extended structures are very suggestive of the Galactic cirrus, while the blobs around NGC 288 and NGC 4833 seem to be related to the two clusters. In this presentation, we will report four representative cases of our survey results and discuss the properties of newly detected sources.

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